Regulator



REGULATOR D. H. WALTON Filed April 28, 1939 Dec. 15, 1942.

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Patented Dec. 15, 1942 UNITED; STMES PATENT OIfFICEY 2,305,211QRGULATon-- 'f' pavia n'. wanen, Hobbs, N. Mex. applicati@ April 28,1939, serial No. 270,47v

I 01. :so- 34) 1o Claims.

This invention relates to new and useful irnprovements in regulators. nl

This invention is an improvement of my copending application, filedAugust 29, 1938, Serial No. 227,384.

One object of the invention is toprovide Virriproved means foraccurately regulating and con' trolling the pressure of a flowing fluid,whereby said pressure may be eiciently maintained yat a desiredpredetermined point. Y

Another object of the invention istopprovide an improved pressureregulator-having avalve for controlling the pressure of the uid iiowingtherethrough, the valve being urged to its open and closed position by apair of opposed pistons which arerexposed to the pressure of .said fluidso as to be actuated thereby, thepistonvwhich opens the valve beingadjustable so as to-momentarily resist opening of said valve until apredetermined pressure is ybuilt up, whereby the valve is moved atintervals so as to intermit the flow of iiuid through said regulator.

An important object of the invention is to provide an improved regulatorof the character described, wherein the regulatorv valve iscontrolled bypistons which have different cross-sectional areas and to whichpressures are applied toi-ac-A tuate.v the same under a predeterminedpressure differential; the device als-o including pressure responsivemeans associated with the pistons sol stili another object of theinvention 'is tc'provide an improved regulator having pressure-.ac-vtuated pistons for controlling the movement of the regulator valve, thepistons being operable by different pressures, one by Vthe-pressure ofthe fluid being regulated and the other by the reduced pressure of saidfluid, or both,` maybeoperated by the unreduced pressure, whereby thedesired pressure reduction may be readily obtained.

A construction ldesigned -to carry out the invention will be hereinafterdescribed, together with other features of the invention. i

The inventionwill bemore readily understood from a reading of thefollowing specification and by reference to -the accompanying drawing,'in which an example of the invention is shown,

, and wherein:

Figure V1 is a transverse, vertical, sectional View of a pressureregulator, constructed in accordance withthe invention and showing theregulator valve in a closed position,

Figure 2` is a similar view with the valve in an unseated or openposition,

Figure A3 is a plan view with a portion shown in section'of theinflatable member, and

Figure 4A is `a horizontal, cross-sectional view, taken on the line 4-4of Figure 1.

In the drawing, the numeral I0 designates a body having a generalT-shape and provided with a circular, vertical Ibore II. A lateral portI2 extends from the bore and a fluid line I3, 'which conducts the fluidto be regulated to the body, is' threaded into the outer end of theport; A fluid' line I4 is Vconnected in the lower end of the verticalbore' II of the body and, manifestly, uid from the supply line I3 entersthe port I2 and then flows downwardly through the bore II totheoutlet'line I4. The latter line conducts the fluid to the point ofconsumption.

An internal, annular ange or ring I5 is formed within the bore II of thebody, being located below the lateral port I2 and being preferably madeintegral with the body. The ring is internally screw-threaded to receivea valve seat member I5 which has an external ange at its upper end. Whenthe seat is in position within the ring, the lower edge of the flangerests on the top of the ring, while the upper fiat end of the seatmember is in horizontal alinement with the .bottom of the lateral *portI2. An axial bore I1 is formed within the seat member and has itsextreme upper end inclined outwardly to provide an annular bevelledvalve seat I8. The remaining portion of the bore is conical or flaredoutwardly toward its lower end, whereby the upper end of said bore issmaller in diameter than the lower end thereof. y

The fluid from the supply line I3 enters the lateral port and ows into aspace or chamber A above the seat member I6 Vand then passes through thebore I1 of said member. The bore Il, -being smaller than the chamber,provides a restriction and, as the uid passes from the bore, it tends toexpand. The flaring contour of the bore permits the fluid to begin itsexpansion immediately upon entering the bore and, thus, expansion ofsaid uid is directed away from the upper end or seat I8 of the memberI6. After passing through the bore, the fluid ows to the space, orchamber, B lbelow the member I6, after which it enters the outlet lineI4.

For controlling the volume of flow through the bore II of the seatmember and thereby controlling the volume and pressure in the outletline I4, an elongate pin or valve member I9 has its lower end movableaxially of the bore I1. The pin I9 is provided with a conical tip 28which is complementary to and which is arranged to engage the bevelledseat I8 of the seat member. Due to the conical tip of the pin, it willbe manifest, as the pinmoves with relation to the seat I8, that thevolume of flow through the bore I'I is regulated or controlled. Theupper end of the pin or member is movable within a vertical cyliny der2| which has its lower end screw-threaded into the upper end of thevertical bore II of the body I0.

A transverse partition 22 extends across the cylinder 2I intermediateits ends so as to provide 4a cylinder 2 3 thereabove.l The upper end cfthe cylinder23 is enlarged toA form a larger cylinder 24 and the upperend of thev latter cylinder sclosed by a suitable Ydome or cap 25 whichis bolted thereto. ,A suitablepacking gasket 26 is interposed betweenthe cylinder24, and the cap 25. It is noted that although the cylinders2I, 23 and 24 have been shown as integral, these cylinders may be madeseparately and screwthreaded, or otherwise` secured,V together. upperportion of the cylinder 2I is provided with a lateral Vent opening orport 2I, whereby the upper end of said cylinder is Open to theatmosphere.

The upper end ,of thepin or valve member I9, which is movable within thecylinder 2|, is tapped to receive the lowerend `of ,a piston rod 21whichis screw-threaded thereinto. The pis ton rodhaving a circular disk28 made integral therewith adjacent its lower end, extends axiallythrough the cylinders 2l and 23 and into the larger cylinder 24. Aflexible, annular piston 29 surrounds the lower end of the rod 21, beingconfined between the upper end of the valve member I9 and a plate3G`which engagesthe lower surface of the disk 28, and being of suchdiameter that its louter periphery engages the wall of the cylinderZI.The lower end, or surface of the piston is formed with an annular recess3| which is arced or concave in cross-section and which is complementaryto an annular. ridge 32 formed on the upper end of the member I9 so` asto provide an annular downwardly curved lip on the lower peripheral edgeof said piston. Thus, when fluid pressure within the chamber A actsagainst the piston, said lip is .positively distorted into sealingengagement with the wall of the cylinder and leakage of pressure pastthe piston is prevented..

A second flexible, annular piston 33, similar to the piston 29, isdisposed within the cylinder 23 so as to surround the rod 27 and isseated upon a plate 34 which is supported by the partition 22. It ispointed out that the piston` 33 remains stationary within itscylinderv23 and thatthe rod -21 Ais arranged to slide therethrough. Theupper end of the piston may be dished as shown at 35. Y

A piston 36 is slidably mounted within the cylinder 24 and is securedtothe upper end of the rod 21. The piston includes an axial, metalliccore 3,1 which has a central, annular flange 31 made integral therewithYand which has a flexible, annular collar 38 surrounding jeach endthereof. The inner end vof each collar engages The ' provide an annularlip 36 at its outer periphery.

The collars and flange are of such diameters that their outer surfacesengage the wall of the cylinder 24. The upper end of the piston 36 issubjected to the pressure of the fluid in the chamber B, which pressurefluid is conducted to the upper end of the cylinder 24 by a conductor3e. The lower end of the conductor 39 is screw-threaded into a lateralport 40 provided in the body le below the seat member I6, while theupper end of said conductor is axially screw-threaded into the dome orcap 25 which closes the upper end of the cylinder 24. A suitablemanually-operated control valve 4I is connected in the conductor 39 formanually controlling the flow therethrough. Also a pressure gauge 42 isconnected in said conductor between the valve and the cylinder 24 toindicate the pressure acting on the piston 36.

From the foregoing, it will be seen that the pin or valve member I9 iscarried by the piston rod 21V whichr isV secured tothe pistons 29 andS6, whereby when said pistons are moved in their respective cylinders,the valve member is moved with relation'to the valve seat i8 of the seatmember I6. lThe upper end of the larger piston 36 isCQnstantly exposedto the pressuire within the chamber B through the conductor 39, whilethe lower end of the piston 29 is vexposed to the pressure inthe chamberA. Since the crosssectional are?! O f -thje upper piston is greater thanthe cross-sectional area of the lower piston, it is manifest that alower pressure above the piston 36 will balance a greater pressureacting below the lower piston. VThe pressure differential necesu sary tomove the pistons is controlled by the ratio of the cross-sectionalareasof the pistonsv to each other and, by varying these areas,different pressure differentials may beset up.

To increase the range of pressures-under which the pistons may operate,an annular inflatable member 43, 'of rubber, fabric or other suitableresilient material, is disposed within the lower end of the largecylinder24. The outer periphery of the member 43 is Vprovided with apair of diametrically 'opposed openings through which extend a pair ofsmallpipes or tubes 44, as is clearly shown in Figure 3. Thepipescommunicate with the interior of the member 'and have their innerends flared or flattened so as to engage and lie contiguous 'to theinnersurface of said member. An annular ring 45, of rubber, or other suitablematerial and having its outer periphery curved or arced, surrounds eachpipe '44 and has its inner end madeintegralwith orsecured to the outerperiphery of the member 43. The .pipes '44 are arranged to be receivedby apair of enlarged openings provided in the wall ofthe cylinder 24,each opening being provided with an annular bushing 46 which has itsbore flared outwardly toward its inner'end. Thus, when the member 43 isin position within the lower end of the cylinder 24, the outer curvedsurfaceof each ring 45 will engage and seat Withinrthe flared bore ofeach bushing 46. The upper surfaceof the inatable member engages theVdished end 38 iof the lower collar 38 of the piston V36,*while the lowersurface of the member is supported by the annular lower end of thecylinder 24 which is bevelled at 24. One of the smallpipes 44 isconnected to the conductor 39 and has a manually operated control valve4l mounted therein for manually, controlling the flow through said pipeto the inflatable member. The other pipe 44 is also provided with amanual valve 48 and is connected to a pressure gauge 49 which indicatesthe pressure acting upon the iniiatable member. It is pointed out thatthe member 43 surrounds the piston rod 21 and has its inner peripherynormally spaced therefrom by a pair of conical packing rings 50. Themember 43 is arranged to be inflated by the pressure within the chamberB through the conductor 39 and pipe 44 and, manifestly, the expansion ofsaid member tends to raise the piston 36, whereby the piston rod 21 ismoved upwardly against the pressure acting on the upper end of saidpiston. With such arrangement, the pressure within the member 43 isadded to the fluid pressure acting against the lower piston 29 to urgethe piston rod upwardly. It is noted that, if desired, the inatablemember could be eliminated, whereby the lower end of the piston 36 wouldbe exposed to aportion of the pressure within the chamber B. In eitherevent, the pressure differential required to move the piston may bevaried by manipulating the manual control valve 41.

In operation, it will be assumed that there is no pressure in the linesI3 and I4 and also that the member 43 is deflated. With such acondition, the valve member I9, together with the piston rod 21 and thepistons 29 and 36 carried thereby, are in a lowered position, the weightof these parts holding them in such position. The bevelled surface ofthe valve member is engaging the bevelled seat I8 of the seat member I6,whereby the bore I1 of said valve seat is closed. When a pressure isturned into the line I3, the pressure fluid will, of course, flow intothe chamber A above the seat member I6. The pressure of this iiuid willact against the valve member I9 and also against the lower piston 29 andwill move this piston upwardly in its cylinder 2|. The upward movementof the piston 29, obviously, will lift Ythe valve member I9 upwardly oiof the seat I8, whereby the fluid may flow through the vseat member andinto the chamber B, as well as into the outlet line I4. The pressurefrom the chamber B, which is less than the pressure in the chamber A'due to the pressure drop across the orice, will enter the conductor 39,flowing past the open valve 4 I, and into the upper end of the enlargedcylinder 24. 'Ihis pressure will act downwardly on the piston 36 andwill tend to move the Valve member back onto its seat. Since thecross-sectional area of the lower piston 29 is smaller than thecross-sectional area of the piston 36, it will be obvious that apredetermined Cil When this predetermined pressure has built up in theupper end of the cylinder y24, the valve member will be moved downwardlytoward its seat, and as soon as a balance between the Pressure in thechamber A and the pressure in the cylinder 24 is obtained, said valvebecomes stationary. Manifestly, this balance of pressure is determinedby the size of the pistons 29 and 36,. By varying the size of thepistons, the balance may be varied. When the balance of pressure isobtained, a constant flow of fluid past the Valve member is had, wherebya constant pressure is maintained in the line I4. Obviously, if thepressure in the chamber B is varied, a change in the position of theVvalve member occurs. sure may be maintained in the line I4.

If it is desired to vary the pressure differential In this manner, aconstant presnecessary to impart movement to the valve member I9, it isonly necessary to open the valve 41 so as to direct a portion of thepressure to the iniiatable member 43. This pressure within the member 43is added to the pressure in the chamber A, which urges the piston rodand valve member upwardly. When a greater pressure is introduced intothe member, a greater pressure must be built up in the cylinder 24 abovethe piston 36 in order to move the same downwardly. Since the'pressurein the cylinder 24 is the same as the pressure in the line I4, it willbe obvious that the pressure in the line I4 is maintained to a higherdegree. in the member 43 will, of course, lower the maintained-,pressurein the line I4. It is again pointed out that the use of the inflatablemember increases the range of pressure under which the device mayoperate.

If desired, the inatable member 43 and its conical packing rings may beentirely eliminated, in which case the pressure differential may bevaried by directing a portion of the pressure within the chamber B intothe lower end of the cylinder 24 so as to act upwardly on the lowercollar 38 of the piston 36. Due to the contour of the exposed ends ofthe stationary piston 33 and the lower collar 38, said piston and pistoncollar will be positively distorted into tight sealing engagement withtheir respective cylinder walls when pressure is introduced into thelower end of the cylinder 24. Thus, leakage of pressure past the pistons33 and 33 is prevented with the result that the piston 36 will be urgedupwardly by the pressure within the lower end of its cylinder.Therefore, it is manifest that the pressure differential necessary toimpart movement to the valve member I9 may be varied by directing aportion of the pressure within the chamber B to to the underside of thecylinder 36 regardless or whether the inflatable member 43 is used ornot.

It is pointed out that fluid under pressure may be sealed within thecylinder 24 and member 43 by closing the valves 4I and I1 after flindhas been introduced into the same, whereby said piston wouldy be exposedto a constant pressure. Thus, a constant resistance would be exertedagainst the pressure of the fluid within the chamber A so as to reducethe pressure or" the fluid owing through the regulator a predeterminedamount. Of course, the valve el may be left open and the valve 41 closedafter the member 43 has been suitably inflated, whereby a predeterminedconstant pressure is provided for aiding in the opening of the valvemember I9.

A lateral port 5I identical to the port 43, is provided in the body I0above the valve seat member I6 so as to communicate with the chamber A.This port is screw-threaded and is normally closed by a plug 52 so as toprevent the escape of pressure. Ir" desired, the lower end of theconductor 39 may be screw-threaded into the port 5I and the port 453closed by the plug 52, whereby the upper side of the piston 36 issubjected to the pressure of the fluid within the chamber A instead ofthe pressure of the iluid within the chamber B. With this arrangement, agreater reduction of pressure will be had due to the difference incross-sectional area of the pistons 36 and 29. 'When the pistons areactuated by the same pressure, it is obvious that only a very smallportion of the pressure acting upon the piston 35 will balance thepressure acting against the lower piston. Therefore, the valvememberwill not be lifted off of its seat until some Reduction of thepressure with.

of the pressure is directed to the underside of the cylinder 36 as wellas its upper ide. It will be apparent that with the cylinder exposed tothe unreduced pressure of the iiuid that the desired result may beobtained by adding the pressure Within the member 43 to the pressurewhich is exerted against the piston 2S. It is again pointed out that thechief advantage of this arrangement is that a greater reduction ofpressure could be obtained.

A pair of radial openings or recesses 53 are provided in the valvemember I9 adjacent its upper end are normally closed by set screws 54which have their outer ends Iiush with the external surface of saidmember. The openings are screw-threaded and have their inner endscommunicating with the tap portion of the member I9, whereby the innerends of the setI screws engage the rod 2l so as to prevent rotation ofsaid member with relation to said rod. By removing the screws 54, theopenings 53 may be engaged by a suitable tool (not shown) for thepurpose of tightening the valve member I9 with relation to the rod 2?.This tightening or raising of the valve member distorts the piston 29into tighter sealing engagement with the wall of the cylinder 2i,whereby said piston tends to resist upward movement cf the valve memberand piston rod due to its frictional engagement with the cylinder wall.With this arrangement, a greater pressure must be exerted against theunderside of the piston 2t before the valve member will be raised fromits seat. When a predetermined pressure is built up within the chamber Asufficient to overcome the frictional engagement of the piston 29 withits cylinder wall, said piston will be rapidly moved upwardly to liftthe valve member with a snap action. The pressure will then flow intothe chamber B and through the conductor S to the upper end of thecylinder 2d. The pressure of this fluid will act downwardly on thepiston 35 `and when a predetermined pressure is built up so as toovercome the frictional engagement of the piston 25 with its cylinder,the piston 35 will be forced downwardly to close the valve with a snapaction. Thus, the valve remains closed until a predetermined pressure isbuilt up to quickly open the same and then remains open until thepressure above the cylinder 3S reaches a predetermined point lat whichtime said valve wili be rapidly closed. Obviously, with the valve memberI9 adjusted to this position, the regulator may be used as a surfaceintermitter so as to intermit the flow of fluid therethrough. Oi'

course, after the member has been adjusted, the

set screws 515 are again inserted within their openings.

If desired, the supply line I3 and outlet line I4 may be reversed,whereby uid enters the chamber B and then ows upwardly through the boreII of the seat member I6, past the pin or valve member i9, into thechamber A and out through the port I2. The conductor 39 is connected inthe port V5I so as to communicate with the chamber A, while the plug 52closes the port fit, With this arrangement, the conical tip 23 of thevalve member is exposed to the pressure within the chamber B, while theupper end of the piston 3E is exposed to the pressure within the chamberA through the conductor 3Q. Since the cross-sectional area oi the piston35 is much greater than the cross-sectional area cf the tip is apparentthat a very low pressure above said piston will balance or overcome anextremely inghzpressure 4acting against said tip. Thus, the

regulator may be used to control the flow of' iluids, carbon dioxide, orothergas whichv might causefreezing, sincethere Wouldbe onlya slight orminimum reduction .in pressure of the fluid when said regulator is usedin this manner. ObviouslyVthe regulator is adapted to be used in variousways and Will perform emciently -at all times'.

t is pointed out that the construction of the device is simple and maybe readily -disassembled for replacement or repair. The .cylinders 2l,23 and'24 may be readily unscrewed from the body and the pistons 29, 33and 36 removed therefrom without a great deal of trouble. The valvemember IE is 'substantially iiush with the lower end of the port .i2through which the pressure fluid enters and the danger of anaccumulation on said member is thereby eliminated. The mov able pistons23 and 36 and the stationary piston 33 areconstructed so as to bedistorted to a tight sealing engagement with their respective cylinderwalls when a pressure is applied thereto and, by such arrangement, theuse of rings or packing elements is unnecessary. The gauge lit, which isconnected to the inflatable member 2, indicates the pressure exertedupon said member, while the gauge d2 which is connected in the conductor39 not only indicates the pressure acting downwardly on the piston35,but aiso ndicates the pressure in the outlet line Ill, since theconductor communicates directly-with said line through the chamber B.

The foregoing description of the invention is explanatory thereof andvarious changes in the size, shape and materials, as well as in thedetails of the illustrated construction, may be made, within the scopeof the appended claims, without departing from the spirit of theinvention.

What I `claim and desire to secure by Letters Patent is:

1. A pressure regulator including, a body having a passage extendingtherethrough, the passage having a restriction therein, means movablewith relation to said restriction for controlling the flow therethrough,means actuated by the differential in pressures on opposite sides ofsaid restriction and connected with the control means for moving thesame, said latter means being spaced apart from the passage of the bodyso as to beunexposed to the main flow through said passage, and flexiblemeans actuated by pressure for varying vthe pressure differential whichactuates said control means.

2. A pressure regulator including, ya body having apassage, arestriction intermediate the ends of the passage whereby a chamber isformed between the restriction and the inlet side of the passage and asecond chamber is formed between said restriction and the outlet Vsideof said passage, valve means movable wit-h relation to the restrictionfor controlling the ow therethrough, means for actuating the valve means-by the differential in pressures in the chambers on oppositevsides ofthe restriction, and, flexible pressure responsive means for varying thepressure diiferential which actuates the last named means.

3. A pressure regulator including, a body having a iiow passage, a valveseat having a restricted opening therethrough mounted within the passageintermediate `the ends thereof, valve means movable with lrelation tothe seat for controlling the flow therethrough, apiston 4means havingits opposite sides vexposed'to Vvthe pressure on opposite sides of thevalve seat, whereby the Vdifferential in such pressures controls themovement of the valve means, and flexible pressure responsive meansassociated with the piston means for varying the differential in saidpressures.

4. A pressure regulator including, a body having a flow passage, a valveseat having a restricted opening therethrough mounted within the passageintermediate the ends thereof, valve means movable with relation to `theseat for controlling the flow therethrough, a cylinder mounted on thebody and having one end communicating with the passage on the inlet sidein advance of the valve seat and having its opposite end communicatingwith the passage on the outlet side thereof beyond the valve seat, apiston means connected to the valve means and movable within thecylinder, whereby the piston is actuated by the differential inpressures on opposite sides of the valve seat, said piston meansexposing different cross-sectional areas at each end to the pressureacting thereagainst, whereby the pressure differential necessary toactuate the piston means is controlled by the ratio of saidcross-sectional areas, and flexible pressure responsive means associatedwith the piston means for varying the pressure differential whichactuates said piston means. y

5. A pressure regulator including, a body having a flow passage, a valveseat having a restricted opening therethrough mounted within the passageintermediate the ends thereof, valve l means movable with relation tothe seat for controlling the flow therethrough, a piston means foractuating the valve means and exposing diierent cross-sectional areas ateach end to the pressure whereby the ratio of said cross-sectional areascontrols the movement of the valve means, and flexible, elastic pressureresponsive means associated with the piston means to urge the same inone direction so as to vary the pressure necessary to move said pistonmeans in an opposite direction.

6. A pressure regulator including, a body having a flow passage, a valveseat having a restricted opening therethrough mounted within the passageintermediate the ends thereof, valve means movable with relation to theseat for controlling the flow therethrough, a cylinder having its lowerend communicating with the flow passage, a piston movable in thecylinder and connected to the valve means, said piston having its lowerend exposed to the pressure in said passage, a second cylinder of largerdiameter than the first cylinder above said rst cylinder, a pistonmovable in the second cylinder and connected with the rst piston, theupper end of the large piston being also exposed to the pressure withinthe ilovv passage, whereby the ratio of the cross-sectional areas oisaid pistons controls the movement of the valve means, and resilient,flexible pressure responsive means beneath the large piston for urgingthe same upwardly so as to vary the pressure necessary to move saidpistons and valve means downwardly.

'7. A pressure regulator including, a body having a flow passage, avalve seat having a restricted opening therethrough mounted within thepassage intermediate the ends thereof, valve means movable with relationto the seat for controlling the iiow therethrough, a cylinder having itslower end communicating with the flow passage, a

, piston movable in the Ycylinder and connected to the valve means, saidpiston having its lower end exposed to the pressure in said passage, a

second cylinder of larger diameter than the rst cylinder above saidfirst cylinder, a piston movable in the 'second cylinder and connectedwith l the first piston, the upper end of the large piston being alsoexposed to the pressure within the flow passage, whereby the ratio ofthe cross-sectional areas of said pistons controls the movement of thevalve means, and resilient means beneath the large piston having elasticwalls for connin-g a pressure fluid to urge said large piston upwardlyso as to vary the pressure necessary to move said pistons and valvemeans downwardly.

8. A pressure regulator including, a body having a Iiow passage, a valveseat having a restricted Vopening therethrough mounted within thepassage intermediate the ends thereof, valve means movable with relationto the seat for controlling the ilow therethrough, a piston meansactuating the valve means and exposing different cross-sectional areasat each end to the pressure whereby the ratio of said cross-sectionalareas control the movement of the valve means, and an inflatableflexible member associated with the piston means and actuated by thepressure to urge the same in one direction so as to vary the pressurenecessary to move said piston means in an opposite direction.

9. A pressure regulator including, a body having a flow passage, a valveseat having a restricted opening therethrough mounted within the passageintermediate the end thereof, valve means movable with relation to theseatfor controlling the` flow therethrough, a cylinder having its lowerend communicating with the iiow passage, a piston movable in thecylinder and connected to the valve means, said piston having its lowerend exposed to the pressure in said passage, a second cylinder of largerdiameter than the f1rst cylinder and above said first cylinder, meansfor conducting the'pressure within the flow passage to the upper end ofthe second cylinder, a piston movable in said second cylinder andconnected with the rst piston, the upper end of the large piston beingexposed to the pressure in said passage, whereby the ratio of thecross-sectional areas of said pistons controls the movement of the valvemeans, the conducting means being so arranged that the pressure in thepassage may be exerted against the lower end as well as the upper end ofsaid piston so as to vary the pressure necessaryto move the pistons andvalve means, said pistons being resilient so as to seal off the bores oftheir respective cylinders when exposed to the pressure within the flowpassage, and an inflatable resilient annular tube beneath the lar-gepiston and having connection with said conducting means for urging saidpiston upwardly so as to vary the pressure necessary to move the pistonsand valve means downwardly.

10. A pressure regulator including, a body having a passage extendingtherethrough, the passage having a restriction therein, means movablewith relation to said restriction for controlling the flow therethrough,means actuated by the differential in pressures on opposite sides ofsaid restriction and connected with the control means for moving thesame, and an expansible annular tube associated with the pressuredifferential-actuated means for varying the pressure diiferen'tial whichactuates the control means.

i DAVID H. WALTON.

